Bruxism or grinding of the teeth is defined as rhythmic or spasmodic grinding of the teeth in other than chewing movements of the mandible, especially such movements performed during sleep. Dental malocclusion and tension-release factors are the usual inciting causes (Dorland's Illustrated Medical Dictionary, 26th edition, W.B. Saunders Co.). It is a significant dental problem afflicting upwards of 30% of the population. As bruxism normally occurs at night and damage to the teeth from bruxism occurs slowly, most patients are unaware of the problem and only notice the damage to their teeth after significant wear has occurred. If left untreated bruxism will slowly result in severe wear of the dentition, cracks and fractures in the teeth and may result in premature tooth loss.
The canine teeth are designed to be protective of the rest of the dentition by their large crown, root morphology and position. The reduction of the protective length of these teeth is commonly the first visible sign that bruxism has occurred. Large well developed masseter muscles are also a feature of severe bruxers. Apart from these indications, bruxers do not often exhibit symptoms such as pain and, as such, it is often difficult for a dentist to convince a patient that a significant problem exists, let alone suggest an appropriate method for prevention.
In treating bruxism, most patients will often not respond to various forms of treatment such as bite or occlusal adjustments and orthodontics. Therefore, as they are unable to consciously prevent the damaging activity from occurring, a bruxism appliance, which forms a physical and softer barrier to grinding teeth, is often the only form of treatment that prevents further damage from occurring.
Bruxism appliances are routinely prescribed to patients at various stages of dental wear as well as after cosmetic dentistry procedures that have replaced the worn teeth from this disorder.
The use of bruxism appliances also presents particular problems as a large percentage of patients when fitted with appliances discontinue the use of their appliances, often because it is difficult to know whether they are still bruxing.
Accordingly, there has been a need for a bruxism appliance and a method of treating a bruxism appliance in order to physically show a patient the degree of grinding they perform and the wear patterns in order to assist in convincing a patient to continue with use of the appliance, or alternatively demonstrate that use of the appliance is no longer required.
In particular, there has been a need for a bruxism appliance and method of treating a bruxism appliance that provides a long-term quantitative indication of the degree of bruxism for subsequent treatments.
A review of the prior art reveals that such a system has not been developed. For example, U.S. Pat. No. 4,557,692 discloses an occlusal splint appliance having a softer inner layer. This reference does not teach the application of an abradable layer to the appliance. Other existing methods involve using multi-coloured plastics for sports mouth guards that are fabricated in the laboratory. These coloured materials are employed for cosmetic purposes only and do not serve any diagnostic purpose. Furthermore, such systems do not allow the dentist to have precise control of the surface thickness as often the surface must be adjusted by the dentist to accommodate the biting surfaces of the opposing teeth. Other methods involve applying easily-removed dyes to the surface to mark the bite of the opposing teeth, which thereby allow the dentist to see the contact areas. These high contact areas are adjusted to create a balanced biting surface. The surface colour is then removed prior to delivery to and use by the patient. Neither of these methods or appliances provide the dentist and patient with an on-going indication of bruxism and its effects.